A cascade of meteors, which are the dust tracks of a
comet's path, will be visible in the skies over the United
States this weekend.

On Friday, Nov. 17, and Saturday, Nov. 18, Earth will
travel through the tail of dust from Comet Tempel-Tuttle. As
the dust particles -- tiny meteoroids -- burn up in Earth's
atmosphere, they give the appearance of "shooting stars,"
called meteors. This display, known as the Leonid meteor
shower, may be most visible over North America's East Coast.
That's because the constellation Leo, where the meteors seem
to come from, will be in a dark part of the sky high above the
eastern horizon.

The Leonids, however, may produce only a minor shower
this year -- about one streak per minute. The Moon's
brightness can also reduce the visibility of the meteors.

"The third-quarter Moon will be in Leo, making the sky
bright and the Leonids a bit difficult to see," said comet
scientist Dr. Don Yeomans of the Jet Propulsion Laboratory,
Pasadena, Calif.

The best way to see the Leonids shower is to block the
Moon's brightness with a hand or tree. On North America's West
Coast this week, look in the general direction of the Moon on
Friday night from 11:30 p.m. until after midnight. Some
meteor activity may be evident the night before at the same
time. From the East Coast, look in the general direction of
the Moon at about 2:50 a.m. on Saturday, when the showers
should be strongest.

Every 33 years, Comet Tempel-Tuttle travels through the
inner solar system. The comet, which is basically a ball of
dust and ice, last passed close to the Sun and was visible
from Earth in March 1998. Near the Sun, the comet's ices begin
to vaporize and the embedded dust particles fall away and
trail the comet in its orbit. Every year, Earth passes
through the trail of debris left behind by the comet, and the
comet dust particles plunge into Earth's atmosphere at some 71
kilometers (44 miles) per second -- fast enough to travel from
Los Angeles to New York in about one minute.